Many aircrafts and other vehicles are being built with smaller, shorter seat backrests for vehicle occupants. In order to support the head, neck, and back of vehicle occupants in seats with shorter backrests, backrest and headrest extension assemblies may be advantageous. The added support of backrest and headrest extension assemblies becomes increasingly important in emergency situations, such as crashes, where supporting the back, neck, and head of vehicle occupants is of utmost importance. However, as seat backrests become shorter, backrest or headrest extension assemblies become larger and heavier. Increasingly heavy backrest or headrest extension assemblies may be difficult for vehicle occupants to move and adjust, particularly from a seated position. Consequently, there is a need in the art for backrest and/or headrest assemblies that are easier to reposition.